Hey, i went to the shop today to have them fix a coolant leak. He asked me if i wanted to do up the AC i said why not. So he pulls out the big can of r134 and the tubes with the gauges and what not. He plugs it in, and gets it going, but he said i had 70lbs of pressure even though it wasnt cold. His explanation was that it has freon but the system is not getting enough juice. He said it would take a while to find but i could be a fuse or something of that nature. Is this accurate? I’m assuming thats a lot of pressure for my system and i guess that means i have refrigerant in it, but why exactly is it not working?
the RPMS do show that the unit is turning on when i push the button so im almost positive its not dead piece.
Did the mechanic add any refrigerant? Or was 70 psi just the initial reading? I’m assuming that was for the low side.
I’m not certain what the optimal range for the low-side pressure is, but if it’s high it could indicate a blockage in the system, or a malfunction in the condenser fan circuit.
The fact that the compressor is engaging would seem to indicate that the pressure isn’t dangerously high. I’d suggest you check to see if your condenser fan comes on when the a/c is on. There are a number of other possible causes, but I’d check that first.
Is this something I’d want to take back to the mechanic? I dont wanna do something wrong or tamper with something and turn into a real expensive problem if he could look at it for a little bit and know whats wrong right away and how to fix it. I’m just glad to was able to replace this impossible to reach coolant tube on a sunday morning i didnt want to press it while i was there. He said it could be a few different things and he’d have to have a little more time to look at it.
How can i look to see if my condesner fan kicks on?
Yes, he did turn the knob and put some refrigerant in it, but i think that was so he could get a good reading, he didnt really add that much cuz he saw the pressure and was like well you all ready got some freon in there.
35 to 45 is where the pressure should be on the low line with the a/c on.if it is at 70 psi like that that then there could be a bigger problem the just freon.also has you car been converted to 134a ??
That’s a good question too. He shouldn’t have been adding R-134a if your system is still charged with freon (aka R-12).
The condenser fan is mounted on the driver’s side of the radiator. It should be turning when the a/c is on. So all you need to do is start the car, let it warm up a bit, turn on the a/c, and take a peek under the hood to see if the fan is turning. Just don’t get too close, and keep your fingers and any loose clothing clear of the fan!
If the fan isn’t turning, you could have a faulty fan motor or relay. If you’re not comfortable with a/c work then you’ll probably want to bring it back to the mechanic and let him deal with it. But just be aware that if there’s a more serious problem it may take a lot of shop labour to correct it, which could get costly.
well as soon as he saw the plugs he told me someone all ready converted it to r134. Seems like so cuz his plug pushed right on and i know r12 systems has a threaded part to them.
If anyone needs some r12, i might be coming into possession of it … if you wanted to buy it to resell it of course unless you have an EPA cert.
it sounds to me like its just a pressure issue. with out getting into the chemistry of r134a, the lower the pressure the colder the air. the optimum pressure for an ac system is above 30psi and below 40psi. At 70psi your ac is not going to be cold, and may damage the pump, but the high pressure switch should not let the pump turn on at that pressure.
That’s not the proper way to do it at all. At the very least the system needs to be under vacuum to accept a full charge of refrigerant. The old oil should also be flushed out, and the receiver/drier should be replaced. Not to mention it’s illegal to vent R-12 to atmosphere…
Ya well i had only 5psi when i tested it on the r12 stuff. 15 year old stuff. Anyways i didn’t know they used freon. The dude who originally told me was just like pull the plug, and cover it with some towels to keep it from spraying everywhere. The vacuum itself is created by being on the low side. Lowside-Vacuum, Hide side is the opposite. So Now i swiched over to r134 have 55psi and running super cold ac. And i live in florida, its hot down here. Took me a total of 5 minutes to recharge ac.
^^^^^Wrong again. your compressor doesnt create vaccum. The pressure differential in the system comes from a restriction in the system. In Honda’s case its created by the TXV. If you never actually put the system into a vacuum by means of an actual vacuum pump you have air in your system which will create moisture and renders your reciever/drier useless. Have fun buying a new a/c system in the future due to moisture contamination and your misunderstanding of the operating systems on your car.
Ya well for a 15 year old ac system is bound to go. For now its nice and cold, colder than it has been for years. I fail to see what the porblem is, personally i think you guys are looking and thinking about this way to hard. Its not a complicated system.
Obviously myself with limited knowledge about the ac system got mine to work when its been 5+ years since it last had cold air blowing in about the same amount of time as it takes to microwave some popcorn. So when my ac system dies in a few years, i will replace everything as it will then been a 16+ year old car.
In the mean time the way i fixed my problem, while it may not of been 100% professional or up to snub in your books, it still works.
you know… i replaced my old cars r12 with r134 and it had no problems for almost four years. a/c worked great right up until it was stolen. of course, i didn’t do it illegally because one of my seals burst and lost all r12. anyway, it should last at least a few years, and these are old cars, the car may not be worth doing a full retrofit.
[QUOTE=G2Magnus;1901540]Ya well for a 15 year old ac system is bound to go. For now its nice and cold, colder than it has been for years. I fail to see what the porblem is, personally i think you guys are looking and thinking about this way to hard. Its not a complicated system.
Obviously myself with limited knowledge about the ac system got mine to work when its been 5+ years since it last had cold air blowing in about the same amount of time as it takes to microwave some popcorn. So when my ac system dies in a few years, i will replace everything as it will then been a 16+ year old car.
In the mean time the way i fixed my problem, while it may not of been 100% professional or up to snub in your books, it still works.[/QUOTE]
Don’t get me wrong, I’m glad it worked out well for you but I think you just got lucky.
Mixing ester and mineral oil makes foam, which does a piss-poor job of lubricating anything, and ester oil eats butyl o-rings and R-12 receiver/drier dessicant bags. So to say that R-134a and R-12 are directly interchangeable is just plain false.
There are plenty of problems that can be temporarily solved with a quick fix, but that doesn’t mean the quick fix is the proper method.
The lowside valve might be able to be vented but i’d check with the guys here on how to do it properly.
Also honestly i just went to autozone and the dude told me to just vent what was in my system and then recharge it with r134. Didn’t know it would cause all this. But hey, lucky or not i at least know the proper way to do it myself now.
[QUOTE=killerelfboy;1902032]so if the high pressure means it wont get cold, do i just need to lower the pressure? How can i do this?
The car blew cold air when i got it in april but it doenst now, if thats any help[/QUOTE]
Did you ever confirm if the condenser fan was working? If it is, then the lack of performance could be due to a restriction or blockage in the system. Possibly a malfunctioning or clogged expansion valve, or even a compressor failure. It’s difficult to say.
I don’t think venting the system is adviseable. It’s important to determine the cause of the issue before you do anything, because it’s not clear to me that the low side pressure is the problem. It could be a symptom rather than a cause. It’s also quite possible that the pressure was within spec to begin with and the mechanic just overcharged the system when he attempted to add refrigerant.
No worries. It’s clear now that you were just acting on what turned out to be poor advice.
